Aircraft propeller



@en -28, 1937o w. W. BRADFORD. .1R 2035242 AIRCRAFT PROPELLER originalFiled Aug. 13, 1951` 2 Sheets-SMH 1 Dec. 28, 937. w. w. BRADFORD, .JR

Original Filed Aug. ,15, 1931 Z-Sheets-Sheet 2 Patented Dec. 28, 1937 y2,103,24e l j AIRCRAFT PROPELLER william W. Bradford, Jr., Bel Air, Ma.,assigner to Howard R. Hyle, Catonsville, Md., Eldridge Hood Young,Baltimore, `Md., and Stanley Turner Holmes, Harford County, Md. l

substitute for application serialf No. 556,909, I

August 13, 1931.

This applicationAugust 31, 1936,.Serial No. 98,772 l Y 6 claims. (o1.17o-472,5.l u

This invention relates to propellers for vairj planes, either forlifting or forcing the plane forward. Y

In carrying out the invention, I provide a at V disc or head which issecured to the propeller shaft, and attached to the upper or forwardside of the disc are radial vanes, covered by a conical hood, except atthe central part of the propeller,

these vanes forming compartments into which air may enter freely at thecentral part of the propeller, each compartment having a restrictedoutlet through which the air is forced at high velocity in a radialdirection. To the under side of the disc is attached a ring whichprojects out- 15.. wardly beyond the disc, this ring being connected tothe disc byan annular flange which is located ashort distance from theperiphery of the disc.

The flange oisets the ring from the rear face of the disc so as to formanannular pocket between the disc and ring. In one form of theinvention, this ring extends parallel with the disc to the periphery ofthe latter, and thence slopes rearwardly, and in another form, thepocket is made somewhat deeper and the ring extends parallel withv thedisc throughout. The ring may be plain, but preferably has radialcorrugations, for a purpose to be hereinafter described. In theaccompanying drawings, k Fig. 1 is a side view of the propeller, thecourse of the air stream being indicated in dotted lines;

Fig. 2 is a plan view of the propeller; Fig. 3 is a section on the line3-3 of Fig. 2; Fig. 4 is a side view of a modified form of pro# peller,and, Fig. 5 is a plan View of the same, partly broken away.

This application is a substitute for my applica.- tion Serial No.556,909 led August 13, 1931, which became abandoned on February 8, 1934.

' 40 Referring to Figures 1 to 3 of the drawings, the

propeller comprises a at supporting disc I having a central openingthrough which extends a hub 2 having a flange 3 to which the disc issecured by bolts 4. The propeller shaft 5 extends 45 through the hub andis suitably secured thereto, as by a key 6 and nut 1. A sheet metal ringI0 is secured to the lower or under side of the disc by a flange 8 atthe inner edge of the ring which oisets the latter from the disc. Theange is 50 affixed to the disc a short distance inwardly from theperiphery of the latter, as shown, thereby forming an annular pocket IIbetween the disc and ring. The ring extends radially outward from theflange, as indicated at 9, as far as the 55 outer edge of the disc, andthence inclines downwardly and; outwardly from the disc as indicatedatlIl'., n vUponthe top or forward side of the discA are. arranged acircular series of radial vanes b, these vanes beingpf generaltriangular shape, equally spaced apart and lying in planes perpendicularto theplane of the disc. Asshown, the edges I2v of the vanes are spacedsome distance from the hub 2 and extend upwardly from the disc, thenceflaring outwardlyl as shown at I2? thence down- 10 wardly and outwardlyas shown at I2b and inclines downwardly to the disc near the peripheryof thelatter. A conical'hoodv I3 is secured to the edgesl'IZb andlinclines downwardly Atothe ends of the vanes andlthence extends parallelwith l5y the ldisc as far as `the periphery Vof the latter, as indicatedat' 13a.. The part 13a is spaced arshort distance from theVdisc,as.shown. By this con--l struction, a circular ,seriesfofradiallyextending air channelsc lis formed, lthese channels being 2O v,

deep at theirinnLer--edges andvconverging toward theirouter endstorestrictedloutlets When, the propellershaft rapidly rotated, the air inthe hannelslwhich may enter freely through their larger `end"s,`is thrwn out by centriiugal force with high velocity through the restrictedends of the channels and a lifting force is applied to the propeller. Mytheory of the operation of the propeller is that the high Velocity airstreams leaving the outlets of the channels 30 past the pocket II causea partial vacuum to be created in said pocket, and over. the ring, andatmospheric pressure causes the high velocity air streams to beideecteddownwardly over and past the inclined surface of the ring, the air 35streams and centrifugal force co-acting to remove the air pressure fromthe upper side of the ring, thereby creating a difference in atmosphericpressure on opposite sides of the ring and disc y which tends to liftthe propeller. I do not, however, wish to confine myself to anyparticular theory of operation. f

In Figures 4 and 5 of the drawings, the structure is the same as in thepreceding gures, except that the ring Illa, instead of being conical, asin said figures, is at and lies parallel with the disc, and is offsetfrom the disc by a deeper ange 8a. The ring is alsoy shown with radialcorrugations I4, which may be employed in either form of ring. For thesame lifting power, it is necessary to make the pocket II deeper, as bylengthening the flange 8a, when the flat type of ring is used, thanwhere the conical type is employed. The radial corrugations are found toincrease the lifting force, possibly by assisting in causing the air tobe thrown off of the ring by centrifugal force.

What I claim is: 1. An air-craft propeller comprising a shaft, a

disc secured centrally to the shaft, a circular series of radiallyarranged members ,forming air channelsV on the" forward side of Vthedisc, said channels being open and relatively deep atv their inner endsand converging to restricted outlets at disc centrally secured to theshaft, a circular series" of spaced radial vanes projectingforwardl'yfrom the disc and having theirouter edges inclined toward theperiphery of the disc, a hood; extending over said inclined edges andforming, with the varies, radial air channels, thefouter edge f' thehood being close to the discV and forming therewith a restricted outletfor the channels, and a ring of sheetI 'materialrconcentric with thedisc, secured to and spaced from the rear sideof the disc and formingtherewith an annular pocket near the periphery of the disc, said ringprojecting radially beyond the disc;

V3. An air-craft propeller comprising a shaft, a disc centrally secured`to the shaft, va circular series of spaced radial vanes projectingforwardly from thev disc and having vtheir outer edges inclined towardthe periphery of the disc, a hood extending over said inclined edges andforming, with the vanes, radial air channels, the outerledge of the hoodbeing close to the disc and forming therewith a restricted outlet forthe channels, and a ring of sheet material concentric with the disc,secured to and spaced from the rear side of the disc and formingtherewith an annular pocket near the periphery of the disc, said ringprojecting radially beyond the disc; and the' partfof said ring whichextends beyond the'margin of the disc being rearwardly inclined.

Vvtherewith a restricted outlet for the channels, and a ring,of sheetmaterial concentric with the disc, secured to and spaced from the rearside of the disc' and forming, therewith an annular pocket near-theperiphery of the disc, said ring projecting radially beyond the disc,and the part of the ring which projects beyond the disc being radiallycorrugated.

5. An air-craft propeller comprising a shaft,

a' disc centrally secured to the shaft, a circular seriesz of spacedradial vanes projecting forwardly from the disc, the edges of the vanesbeing spaced from thev lshaft and inclined forwardly anqput; wardly andthenceV 'rearivvardlyv land 'outwardly and terminated a shortdistancefrorn thefperipr':l ery of the disc, a conical hood, formingwith the vanes, a series of air channelsQsaid hodextending oversaidrearwardly and'outwardlyinclined edges, said hood having its outermargin` spaced a short distance from the disc and'fiared out-j wardlyover the disc, forming therewith airestricted outlet for the airchannels and a ring fof sheet material, concentric with the disc,secured to and spaced from the rear side of the disc and formingtherewith an annular pocket' near vthe periphery 'of the disc, said ringprojecting radially beyond the disc. l Y j 6. An air-craft propellerkcomprising a shaft, adiscsecured 'centrally to said shaft, means on'the disc for forcing air radially outward beyond the disc as the latterrotates, and a Aring .of 4sheet material connected to vthe rear side ofthe Vdisc inwardly from the periphery'of the disc and offset from thedisc, said ring projecting radially beyond the disc; f

WILLIAM W. BRADFORD, JR,

